Multi-zone food holding bin

ABSTRACT

A multi-zone food holding bin has a continuous food supporting surface with multiple food holding zones. Each food holding zone is independently controllable so that different food temperatures may be maintained in adjacent food holding zones.

BACKGROUND

Often the success of a restaurant depends, at least in part, on how quickly customers can be served with ordered food items and also on the quality of the food items when served. If the rate of food preparation equals the rate at which the food is ordered and sold, a restaurant can theoretically have freshly-prepared foods ready to serve for customers as they arrive. Since it is not always possible to match food production with customer ordering rates, and since certain fast food restaurant customers expect to receive their ordered food items quickly, many fast food restaurants prepare various food items in advance and keep them ready for sale until a customer arrives and purchases a pre-cooked food item.

To facilitate the food holding process, holding bins or holding ovens are often used to keep the food warm. Known holding bins can allow a cooked food item to be inserted from one side and taken from the opposite side whereby food preparers add food to the holding bin on one side and food servers on the opposite take food from the holding bin. Food holding bins in which the cooked food item is inserted and removed from the same side are also known. The food items in the holding bins are kept warm by heating elements. However, food holding time in known holding bins or ovens is somewhat limited, generally less than 15 or 20 minutes before the food item must be discarded. As a result, restaurants can only keep a limited amount of pre-cooked food items on hand and often a significant amount of the pre-cooked food items must be discarded before they are sold, resulting in additional costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a multi-zone food holding bin;

FIG. 2 is a front elevational view of the multi-zone food holding bin of FIG. 1;

FIG. 3 is a rear elevational view of the multi-zone food holding bin of FIG. 1;

FIG. 4A is a partially cut-away top perspective view of an alternate embodiment of a multi-zone food holding bin and FIG. 4B is a close up of a shelf portion of the multi-zone food holding bin from circle 4B in FIG. 4A;

FIG. 5 is a partially cut-away bottom perspective view of the food holding bin of FIG. 4; and

FIG. 6 is a partially cutaway top perspective view of yet another alternate embodiment of a multi-zone food holding bin.

DETAILED DESCRIPTION

Turning now to FIGS. 1-3, a multi-zone food holding bin 10 includes two separate food holding compartments 50. Additional food holding compartments 50 may also be included as explained in further detail below. Each separate food holding compartment 50 includes two or more separate food holding zones, for example, a first food holding zone 51 a and a second food holding zone 51 b. As illustrated in FIGS. 1-3, the multi-zone food holding bin 10 also includes a third food holding zone 51 c and a fourth food holding zone 51 d. The food holding zones 51 a, 51 b, 51 c, and 51 d are illustrated as being separated from one another by a dashed line in FIGS. 1-3. The dashed lines are for illustration only. The food holding zone need not have their boundaries identified with any sort of line or other indicia in food holding compartment 50. Each food holding zone 51 a, 51 b, 51 c, and 51 d can be configured to maintain a different food holding temperature, advantageously allowing the operator to hold different food products with different heating requirements in the same food holding compartment 50, thereby permitting increased energy efficiencies to be realized and potentially reducing the space requirements for holding different foods. For example, a first food product such as french toast can be held at a first temperature in the first food holding zone 51 a and a second food product such as eggs can be held at a second temperature in the second food holding zone 51 b, the second temperature capable of being independently set to be different from the first temperature. Similarly, a third food product such as sausage patties can be held at a third temperature in the third food holding zone 51 c, the third temperature capable of being independently set to be the same or different from the first and second temperatures. And a fourth food product such as hash browns can be held at a fourth temperature in the fourth food holding zone 51 d, the fourth temperature capable of being independently set to be the same or different from the first, second, and third temperatures. This can be particularly useful for restaurants during lower demand times and also for smaller restaurants and retail operations.

In one embodiment of the cabinet 10, all of the compartments 50 are heated. In another embodiment, some compartments 50 may be refrigerated while other compartments 50 are heated. In yet another embodiment, one or more compartments 50 can be selectively heated or refrigerated.

The cabinet 10 includes a chassis 15. As illustrated, the chassis 15 includes a top panel 20, a bottom panel 25, left-side panel 30, right side panel 35, an open front face 40 and an open rear face 45. When the rear face 45 is open and uncovered, food items can be inserted by a first operator responsible for initial food preparation and passed through to a second operator responsible for final food preparation, for example, packaging and customization of a food product for serving to the ultimate customer. In another embodiment, the rear face 45 may be “closed” and provided by a rear panel such that access into the cabinet 10 is only provided by the open front face 40. The panels may be insulated to reduce heat transfer between the interior of the cabinet 10 and the atmosphere surrounding the cabinet 10.

The cabinet 10 illustrated in FIG. 1 is sized, shaped and arranged to have two compartments 50, however, the cabinet can have any number of compartments 50, including a single compartment 50. For clarity, the two compartments 50 depicted in FIGS. 1-3 are denominated using the letters A and B. The “A” compartment is the top or uppermost compartment 50 and the “B” compartment is the bottom or lower-most compartment 50.

In the embodiment illustrated in FIG. 1, the top or “A” compartment is defined by the left and right sidewalls 30 and 35, the chassis top panel 20 and a first or upper-most shelf 52. Compartment “B” is defined by the two sidewalls 30 and 35, the first or upper-most shelf 52, and the chassis bottom panel 25. In cabinet embodiments having only one compartment 50, the single compartment is defined by opposing, left and right sidewalls 30 and 35, a chassis top panel 20 and a chassis bottom panel 25. For brevity, cabinet construction and operation is described with regard to a cabinet 10 having two compartments 50 in FIGS. 1-3. However, other embodiments may have more than two compartments 50 or less than two compartments 50. For example, the embodiments illustrated in FIGS. 4A, 4B, 5, and 6 have four compartments 50. Again, other configurations are also possible.

The shelf 52, which partially defines the compartments 50, is planar or at least substantially planar and supported in the chassis 15 at opposing side ends by the two chassis side walls 30 and 35. The shelf 52 includes a planar and continuous top surface, which forms a planar and continuous bottom surface 53 of the upper compartment 50. The planar and continuous bottom surface 53 of the upper compartment 50 is configured to support food items (as used herein, the term “food item” includes but is not limited to containers or trays containing food products such as cooked protein patties, fried foods, and the like). In the illustrated embodiment, food items can be placed onto the planar and continuous bottom surface 53 and removed from the planar and continuous bottom surface 53 through the open front face 40 or through the open rear face 45. Because the bottom surface 53 is planar and continuous and substantially free of any dividing walls or other structure between the holding zones 51 a, 51 b, 51 c, and 51 d, cleaning of the bottom surface 53 can be easily accomplished.

A face plate or bezel 92 is generally attached to the front of the chassis 15. For example, the bezel can be attached to the sidewalls 30 and 35 of the chassis 15 so as to be disposed underneath a top surface of the shelf 52. In cabinet embodiments having only one compartment 50, the bezel 92 may be attached to either of the chassis top or bottom panels 20, 25 of the cabinet 10. In the illustrated embodiment of FIGS. 1-3, the bezel 92 is set forward from the shelf 52 by a space 55. The space 52 forms a slot in which one or more latches 23 translate and/or rotate to release lids held in lid holding ledges 31 as will be discussed further below.

The bezels 92 include information displays and controls, which are collectively identified by reference numeral 93. Although the chassis 15 can include panels concealing the heat generating devices located within a shelf, the bezel 92 also can conceal heating elements, which are located within the shelf 52, such that a separate panel is not present.

Each food holding zone 51 a, 51 b, 51 c, 51 d may include a dedicated display and control 93 a, 93 b, 93 c, 93 d, respectively. In the embodiment illustrated in FIGS. 1-3, the display and control 93 a, 93 b, 93 c, and 93 d displays the temperature setpoint of a respective food holding zone 51 a, 51 b, 51 c, 51 d. Moreover, each display and control 93 a, 93 b, 93 c, 93 d controls heating elements that maintain the temperature setpoint of the respective food holding zones 51 a, 51 b, 51 c, 51 d. The displays and controls 93 a, 93 b, 93 c, 93 d may be grouped together (i.e., arranged horizontally beneath the respective food holding zone 51 a, 51 b, 51 c, 51 d) in the bezel 92 for a corresponding compartment 50. In the embodiment illustrated in FIGS. 1-3, a single bezel 92 is used to provide the display and control elements for two vertically adjacent compartments 50, but of course discrete bezels can also be used. The displays and controls 93 a, 93 b provide a user graphical interface to one or more controllers (not shown) for the cabinet.

Each food holding zone 51 a, 51 b, 51 c, 51 d may be sized to receive a food holding tray 27 and lid 21 (see FIG. 2 where the tray 27 is illustrated in broken lines). In order to conveniently store the lid 21, each food holding zone 51 a, 51 b, 51 c, 51 d may also include a dedicated lid holding shelf 31 that is sized to receive and store the lid 21 when the lid 21 is desired for use in combination with a food holding tray 27, such as when protein patties are contained within the tray 27. Generally, a top surface 27 a of a food holding tray 27, when received in the lid holding shelf 31, is substantially flush with a top surface of the lid holding shelf 31 such that when the tray 27 is disposed in the food holding zone 51 c, the tray 27 can be in contact with and engaged by the lid 21 in the lid holding shelf 31 so as to retain moisture within the tray 27-lid 21 assembly. In some embodiments, the lid holding shelf 31 may be provided by formed sheet metal. In other embodiments, the lid holding shelf 31 may be provided by a wire form. Other structures are also possible.

Adjacent to each lid holding shelf 31 is one or more latches 23 having an open center portion. In the illustrated embodiment, the latches 23 have a round or curved body 29 that is rotatable and/or translatable (because of the open center) about a retaining element such as a pin or screw (not shown). In other embodiments, the latches 23 may have straight or angled outer surfaces that form other shapes, such as a square, a pentagon, a hexagon, or any other polygonal shape. The latches 23 may be disposed adjacent an opening into the food holding compartment 50 above the lid holding shelf 31. In one example, the latches 23 may be captured on a cylindrical retaining element between the chassis 15 and a top of the food holding compartment 50 above the lid holding shelf 31. In other embodiments, one or more washers (not shown), such as metal, nylon, or plastic washers, may be disposed on the cylindrical retaining element to space the latches 23 apart from the bezel 92 and the shelf 52 to prevent metal galling and/or to reduce friction between the latches 23 and the bezel 92 or shelf 52 to ease actuation of the latches 23.

The round body 29 may be oriented substantially parallel to a front face of the chassis 15 or the bezel 92 in a locked or default position, as illustrated by reference numeral 23 a, which prevents inadvertent removal of a lid 21 from the lid holding shelf 31 when a tray 27 is withdrawn. The latch 23 is in its default or locked position simply because of gravity, thus re-positioning the latch to an unlocked state advantageously requires simply overcoming the weight of the latch 23 by translational and/or rotational movement. The round body 29 may be rotated and/or translated upwards relative to the bezel 92 or lid holding shelf 31 from the locked or default position to an unlocked position, as illustrated by the dotted lines referencing latch 23 between food holding zone 51 a and food holding zone 51 b in FIG. 1; this rotational and/or translational movement of the latch 23 about the retaining element allows facile insertion or removal of a lid 21 to/from the lid holding shelf 31. The round body 29 may be mounted on a retaining element such as a pin (not shown), which retains the round body 29 and allows the round body 29 to translate along the open center portion and/or to at least partially rotate about the pin when the round body 29 translates. The lid holding shelf 31 also allows the food holding compartment 50 to have the planar and continuous bottom surface 52 by storing the lids 27 a in an elevated position, with the lid holding shelf 31 being suspended above the continuous bottom surface 52, typically by fixedly attaching a base of the shelf to a top surface of the food holding compartment 50 at one or more positions. Such continuous planar and continuous bottom surfaces 52 are much easier to clean than compartmentalized or divided heating chambers. Furthermore, the round body 29 of the latch 23 and the translation/rotation movement of the latch allow easy removal of the lids 27 from the lid holding tray 31 with one hand while positioning the latch 23 to the unlocked position with another hand.

From a purely functional standpoint, a preferred latch 23 might simply include a locking portion that is able to prevent inadvertent displacement of the lid 21 when the tray 27 is purposefully removed. Thus, a number of different configurations and shapes can be used for the latch 23. The latch 23 illustrated here with the round body 29, on the other hand, has an alternative, ornamental arrangement for the round body 29 in which the edges of the round body 29 include an arc-shaped, curved surface. This illustrated arrangement may add to the cost of manufacture, so the illustrated latch does not provide all of the possible economic advantages that might be derived from the invention. On the other hand, this arrangement is believed to be aesthetically pleasing and is likely to be recognized and relied upon by purchasers to identify the source of the food holding bin.

FIGS. 4A, 4B, and 5 are perspective views of an alternate embodiment of a multi-zone food holding bin 10, the embodiment of FIGS. 4A, 4B, and 5 including four separate food holding compartments 50. The embodiment of FIGS. 4A, 4B, and 5 is identical to the embodiment of FIGS. 1-3 with the exception that the embodiment of FIGS. 4A, 4B, and 5 includes four food holding compartments 50 instead of two. Thus, reference numbers identifying identical elements are the same in FIGS. 1-3 and in FIGS. 4A, 4B, and 5. Moreover, elements not illustrated in one of the embodiments are understood to be present in the other embodiment. For example, the embodiment illustrated in FIGS. 4A, 4B, and 5 includes cut-away views showing internal components that are not visible in FIGS. 1-3. Nevertheless, these internal components are understood to be present in the embodiment illustrated in FIGS. 1-3 as well.

Similar to the embodiment of FIGS. 1-3, each separate food holding compartment 50 in the food holding bin 10 of FIGS. 4A, 4B, and 5 includes at least two separate food holding zones, a first food holding zone 51 a and a second food holding zone 51 b. Each food holding zone 51 a, 51 b is configured to maintain a different temperature. Of course, it is not necessary for the food holding zones 51 a, 51 b to be operated at different temperatures in practice.

The cabinet 10 illustrated in FIG. 4A is sized, shaped and arranged to have four compartments 50, however, cabinets in accordance with the disclosure can have any number of compartments, including a single compartment.

In FIG. 4A, the first or top compartment is defined by the left and right sidewalls 30 and 35, the chassis top panel 20 and the first or upper-most shelf 52. The second compartment is defined by the two sidewalls 30 and 35, the shelf 52 for the first compartment and the second shelf 52. The third compartment is defined by the two sidewalls 30, 35, the second shelf 52 and the third shelf 52. The fourth compartment is defined by the two sidewalls 30 and 35, the third shelf and the chassis bottom 25.

The shelves 52, which partially define the compartments 50, are planar or at least substantially planar and supported in the chassis 15 at their opposing side ends by the two chassis side walls 30 and 35. Each shelf 52 forms a planar and continuous top surface, which defines a planar and continuous bottom surface 53 of the compartment 50. The planar and continuous bottom surface 53 of the compartment is configured to support food items (as mentioned above, the term “food item” includes but is not limited to containers or trays containing food products such as cooked protein patties, fried foods, and the like). Food items can be placed onto the planar bottom surface 53 and removed from the planar bottom surface 53 through the open front face 40 or through the open rear face 45.

Each food holding zone 51 a, 51 b may include a dedicated display and control 93 a, 93 b, respectively. Each display and control 93 a, 93 b displays the temperature setpoint of a respective food holding zone 51 a, 51 b. Moreover, each display and control 93 a, 93 b controls heating elements that maintain the temperature setpoint of the respective food holding zones 51 a, 51 b. The displays and controls 93 a, 93 b may be grouped together (i.e., arranged horizontally beneath the respective food holding zone 51 a, 51 b) in the bezel 92 for a corresponding compartment 50. In the embodiment illustrated in FIGS. 4A, 4B, and 5, a single bezel 92 is used to provide the display and control elements for a single compartment 50. The displays and controls 93 a, 93 b provide a graphical user interface to one or more controllers (not shown) for the cabinet.

Cabinet control and control of the food holding zone 51 temperature is effectuated in part by using one or more microcontrollers or microprocessors 97 in combination with temperature sensors 99. US 2011-0114624 A1 entitled “Food Holding Cabinet Power Supplies with Downloadable Software,” the entirety of which is hereby incorporated by reference herein, discloses among other things, apparatuses and methods by which compartments of a food holding cabinet can be controlled using microprocessors having downloadable software. Compartment temperature control is preferably effectuated using a semiconductor temperature sensor, thermally coupled to each food holding zone 51 and electrically connected to a processor, such as those disclosed in US 2011-0114624 A1.

A semiconductor apparatus and method for measuring temperature of a plate or shelf in a food holding cabinet is disclosed in U.S. Pat. No. 8,247,745, which is entitled “Temperature Sensor for a Food Holding Cabinet” the entirety of which is hereby incorporated by reference herein.

The shelf 52 includes a lower heating element 67 for the first food holding zone 51 a in a first or top food holding compartment 50, and an upper heating element 65 for a second food holding zone 51 a in a second or lower food holding compartment 50, directly below the first food holding compartment 50. While the first heating element 67 is illustrated as providing heat to the upper first food holding zone 51 a (from below) and the second heating element 65 is illustrated as providing heat to the lower first food holding zone 51 a (from above), heating elements that are not shown include at least a heating element that provides heat to the upper first food holding zone 51 a from above and another heating element that provides heat to the lower first food holding zone 51 a from below. Additionally, the second food holding zones 51 b, which are adjacent to the first food holding zones 51 a, are heated in the same way as the first food holding zones, but with independent heating elements. The heating elements of the second food holding zone 51 b are independently controllable from the heating elements of the first food holding zones 51 a. Referring to the inset FIG. 4B, the shelf 52 includes an upper thermally conductive plate, which forms the continuous planar bottom surface 53 of the first (or upper) food holding compartment 50 and a lower thermally conductive plate, which forms a continuous planar upper surface 54 of the second (or lower) food holding compartment 50. The planar bottom surface 53 and the planar upper surface 54 are spaced apart from each other by a distance sufficient to accommodate the inclusion of at least two heating elements, which are illustrated in the figures as the separate first heating element 67 and the separate second heating element 65, respectively. Insulative materials may be provided between the first heating element 67 and the second heating element 65 to provide better thermal control over the food holding zones 51 a, 51 b. The first heating element 67 is a lower heating element for the upper food holding compartment 50 and the second heating element 65 is an upper heating element for the lower food holding compartment 50.

The continuous planar bottom surface 53 of the top food holding compartment 50 and the continuous planar upper surface 54 of the bottom food holding compartment are preferably made of aluminum, between about one-eighth and about one-quarter inch-thick. Alternate embodiments of the shelf 52 may use a thermally-conductive panel made of glass-ceramic or an ultra-low expansion glass for one or both of the lower surface 53 and the upper surface 54. Glass-ceramics and ultra-low expansion glass are considered herein to be “good” thermal conductors in that their conduction of heat energy is localized. Such materials also make excellent shelves for a heated, multi-zone food holding bin because they permit localized areas of a shelf to be heated to a first temperature, without having the entire shelf reach the same temperature.

The first heating element 67 is disposed between the planar bottom surface 53 and the planar upper surface 54 and the first heating element 67 is in thermal communication with the planar bottom surface 53. The first heating element 67 may be mechanically attached to the planar bottom surface 53 by a thermally-conductive adhesive, in one embodiment. The first heating element 67 may also be attached to the planar bottom surface 53 by brackets or clamps.

The second heating element 65 is disposed between the planar bottom surface 53 and the planar upper surface 54 and the second heating element 65 is in thermal communication with the planar upper surface 54. The second heating element 65 may be mechanically attached to the planar upper surface 54 by a thermally-conductive adhesive, in one embodiment. The second heating element 65 may also be attached to the planar upper surface 54 by brackets or clamps.

In the embodiment illustrated in FIGS. 4A, 4B, and 5, the first heating element 67 can be located above the second heating element 65 but in thermal communication with the planar bottom surface 53 such that when the temperature of the first heating element 67 rises, it provides heat energy into the planar bottom surface 53 in a region around the first heating element 67, and more specifically, within the first food holding zone 51 a of the first or top food holding compartment 50. Thermally insulating the first heating element 67 from the planar upper surface 54 and thermally insulating the second heating element 65 from the planar bottom surface 53, enables the first heating element 67 to provide a first amount of heat energy into the planar bottom surface 53 (and thus into the first food holding zone 51 a of the upper food holding compartment 50), while the second heating element 65 provides a second amount of heat energy into the planar upper surface 54 (and thus into the first food holding zone 51 a of the lower food holding compartment 50). In this manner, each food holding zone 51 a, 51 b may be configured to have an independent and unique temperature profile from top to bottom of the food holding zone 51 a, 51 b. For example, one food holding zone 51 a, 51 b may have a temperature profile that generally decreases from top to bottom (i.e., the top of the food holding zone 51 a, 51 b is hotter than the bottom of the food holding zone 51 a, 51 b).

In some embodiments, the second heating element 65 may comprise a radiant heating source that projects radiant heat through the planar upper surface 54 and into the first food holding zone 51 a of the lower food holding compartment 50. In other words, in one embodiment, the first heating element 67 provides heat energy into the first food holding zone 51 a of the upper food holding compartment 50 through conduction, while the second heating element 65 provides heat energy into the first food holding zone 51 a of the lower food holding compartment through radiation. Similarly, a radiant heating element may be provided at a top interior surface of the first or top food holding compartment 50 beneath the chassis top panel 20. In this manner, the top and bottom of a food product placed into the first food holding zone 51 a may absorb different amounts of heat energy, customized depending on the type of food product. Thus, the heat profile in the first food holding zone 51 a may be customized vertically as well as differentiated from the heat profile in the second food holding zone 51 b. As a result, a single food holding compartment 50 (e.g., the upper compartment in FIGS. 4A and 5) may be customized to store different types of food products in the first food holding zone 51 a and the second food holding zone 51 b, each food holding zone 51 a, 51 b having a different temperature profile. As a result, the disclosed food holding bin 10 is flexible in that it can keep multiple different types of food products at their ideal holding temperatures in a single food holding compartment, thus increasing efficiency and adaptability to different food demands.

Because of this flexibility, it has been found that a food holding bin constructed in accordance with the disclosure can extend the palatability time of a food item by a factor of two or more.

An alternate embodiment, as illustrated in FIG. 6, may use the thermoelectric effect provided by one or more Peltier devices 80 to heat one or more of the compartments 50.

The thermoelectric effect is a direct conversion of a temperature difference into an electric voltage and vice versa. When a voltage is applied to a thermoelectric device, a temperature difference is created across the two sides of the device. The temperature difference created in response to an applied voltage is known as the Peltier effect. Devices that produce temperature differences in response to an applied voltage are considered herein to be Peltier devices. A Peltier device 80 is therefore considered herein to be a heat source or heating element.

Peltier devices have a “cold” side and a “hot” side. The cold side absorbs heat whereas the hot side emits heat. Heat emitted from the hot side includes at least some of the heat absorbed from the cold side. A Peltier device 80 is therefore considered herein to be a solid-state heat pump or heat-sinking device.

FIG. 6 is a cutaway view of another embodiment of a point-of-use holding cabinet using Peltier devices to heat the food holding compartments 50. In one embodiment, one or more Peltier devices 80 are “sandwiched” between, and in thermal communication with the bottom planar surface 53 and the upper planar surface 54 described above. Electrical energy is provided to the Peltier devices 80 through wires 85, under the control of a controller.

“Sandwiching” the Peltier devices in a shelf 52 as shown in FIG. 6 provides a shelf 52 cold on one side and hot on the other. Such a shelf 52 structure thus enables a dual-mode food holding cabinet 10 having a “first” food holding compartment 50 that is warm and a vertically adjacent “second” food holding compartment 50 that is cold.

Temperature control of a thermoelectric, Peltier device 80 may be accomplished by controlling the electric energy provided to the device. Temperature control of one side of the Peltier device 80 can also be effectuated by controlling heat transferred into or out of the opposite side of the device, as described in US 2010-0307168 A1, entitled “Thermo Electric Cooler,” the disclosure of which is incorporated herein by reference in its entirety.

In another embodiment of a multi-zone food holding bin 10, multiple Peltier devices 80 are mounted between the bottom surface 53 and the upper surface 54 but have only their hot sides thermally coupled to the bottom surface 53 and to the upper surface 54. Air is then moved through the inter-plate space to heat the cool sides of the Peltier devices therein.

Peltier devices as disclosed herein and similar heat transfer devices are thermally coupled to the shelf 52, preferably by way of mechanical attachment to at least one of the plates that form the lower planar surface 53 and the upper planar surface 54. Mechanical attachment and the resultant thermal coupling is preferably accomplished by a thermally-conductive adhesive, however, clamps that are attached to a plate by screws driven into a plate can also be used.

The shelves are mechanically coupled to the side panels 30 and 35. The side panels are also preferably made from thermally-conductive material such as aluminum. Thermally coupling a heat transfer device to one or more plates that comprise a shelf therefore also thermally couples the heat transfer device to the side walls and thus to the compartment. Heat transfer devices coupled to a shelf are therefore also thermally coupled to the corresponding compartment.

While the temperature of a Peltier device can be controlled by controlling the heat dissipated from the hot side and/or the heat absorbed into the cold side, cabinet embodiments disclosed herein preferably control compartment temperature using one or more semiconductor temperature sensors, thermally coupled to one or more of the thermally-conductive structures that comprise a compartment. Cabinet embodiments disclosed herein preferably use a semiconductor temperature sensor that is directly coupled and therefore thermally coupled to the heated surfaces 53 and/or 54 provided by the shelves 52.

Semiconductor temperature sensors used in preferred embodiments disclosed herein are disclosed in U.S. Pat. No. 8,247,745, which is entitled “Temperature Sensor for a Food Holding Cabinet” the entirety of which is hereby incorporated by reference herein, especially the teachings of the structure and use of a semiconductor temperature sensor.

Thus, suitable heating elements for use in accordance with the disclosure include electrically-resistive heating elements, such as heated coils, radiant heating elements that provide heat energy via radiation, and devices and ancillary equipment that provide heat to a working fluid. As described above, Peltier devices may also be used as heating elements in accordance with the disclosure.

The foregoing description is for purposes of illustration only and not for purposes of limitation. The true scope of the invention is set forth by the appended claims. 

What is claimed is:
 1. A multi-zone food holding bin comprising: a chassis having a front face and an opposing rear face; a first food holding compartment within the chassis, the first food holding compartment having at least a first opening, the first opening being open, uncovered and located at the front face of the chassis, the first opening being configured to allow food items to be placed into and removed from the first food holding compartment; a continuous and planar surface forming a bottom of the first food holding compartment, the continuous and planar surface extending completely to the front face of the chassis, the continuous and planar surface comprising Aluminum; a first food holding zone formed in the first food holding compartment, the first food holding zone having an independently controllable radiant first heating element disposed at a top portion of the first food holding compartment, and an independently controllable conductive second heating element disposed at a bottom portion of the first food holding compartment; a second food holding zone formed in the first food holding compartment, the second food holding zone having an independently controllable radiant third heating element disposed at the top portion of the first food holding compartment and an independently controllable conductive fourth heating element disposed at the bottom portion of the first food holding compartment; and a food holding tray disposed in the first food holding compartment, the food holding tray resting on the continuous and planar surface, wherein the first food holding zone and the second food holding zone are adjacent one another across the continuous planar surface and the first food holding zone is configured to maintain a first temperature and the second food holding zone is configured to maintain a second temperature, the first temperature and the second temperature capable of being different than one another, and wherein the first independently controllable heating element heats the food holding tray radiantly from above and the second independently controllable heating element heats the food holding tray conductively from below.
 2. The food holding bin of claim 1, further comprising: a second food holding compartment disposed below the first food holding compartment within the chassis, the second food holding compartment having at least a first opening, the first opening being open, uncovered and located at the front face of the chassis, the first opening being configured to allow food items to be placed into and removed from the food holding compartment; and a shelf located between the first and second food holding compartments, the shelf comprising a first side and a second side, the first side facing into the first food holding compartment, the second side facing into the second food holding compartment, the second and fourth heating elements being disposed in the shelf and in thermal communication with the first side, the second and fourth heating elements being capable of providing different amounts of heat energy into the first and second food holding zones of the first food holding compartment; and a controller operatively coupled to the second heating element and to the fourth heating element, the controller being configured to independently operate the second heating element and the fourth heating element.
 3. The food holding bin of claim 1, wherein the first and second food holding compartments each have a second opening, uncovered and located at the rear face of the chassis.
 4. The food holding bin of claim 1, wherein the first heating element is adapted to output more heat energy than the second heating element.
 5. The food handling bin of claim 1, further comprising a lid located in a top portion of the first food holding compartment, the lid capable of being inserted into a shelf above the continuous and planar bottom surface.
 6. The food holding bin of claim 5, further comprising a latch located adjacent to the shelf, the latch having a body including an open center portion, the latch being rotatable or translatable relative to the shelf between a locked position and an unlocked position.
 7. The food holding bin of claim 1, further comprising a lid on the food holding tray.
 8. The food holding bin of claim 1, wherein at least one of the first heating element and the second heating element is an electrically resistive heating wire.
 9. A method of maintaining different temperatures in a food holding compartment of a food holding bin, the method comprising: providing a food holding compartment with a first food holding zone and a second food holding zone adjacent to one another, the first and second food holding zones sharing an uninterrupted continuous planar bottom surface comprising Aluminum, the uninterrupted continuous planar bottom surface extending to a front face of a chassis forming the food holding compartment, and a food holding tray disposed in the food holding compartment, the food holding tray resting on the uninterrupted continuous planar bottom surface, the first food holding zone including a first independently controllable radiant heating element that heats radiantly from above and also includes a second independently controllable conductive heating element that heats conductively from below, and the second food holding zone includes a third independently controllable radiant heating element that heats radiantly from above and also includes a fourth independently controllable conductive heating element that heats conductively from below; independently setting a first temperature in the first food holding zone by operating the first independently controllable heating element and by operating the second independently controllable heating element; and independently setting a second temperature in the second food holding zone by operating the third independently controllable heating element and by operating the fourth independently controllable heating element, wherein the first temperature is different from the second temperature.
 10. The method of claim 9, further comprising providing more heat energy from the first heating element than from the second heating element. 